The present invention relates to a printer particularly a matrix printer of the variety in which different print media are to be fed to the printer through separate guide and feed channels arranged for example on different sides of the printer casing.
Print medium feed devices include frequently switching arrangements and feeling or scanning levers which can be pivoted right into the path of the respective print medium such as sheets a web of paper so as to monitor the leading edge of such sheet and to monitor more generally the presence or absence of sheet stock in the respective feed channel. In the case of a printer having multiple feed path care should be taken so that only one feed path actually provides for feeding at a time.
The aforementioned switching device for detecting and monitoring absence or presence of sheet stock in a feed path are usually provided for purposes of furnishing an indication whether or not the printer is actually in an operating state in which printing can occur on a print medium; whether the medium has sufficiently advanced into the printer; whether the medium has or has not yet run out. In case there is no such print medium in the printer, obviously printing cannot take place which is possible if the sheet stock is exhausted, a roll of a paper has run out, or torn off, or bunched up elsewhere etc. The sheet stock is provided with edge perforations for purposes of transport.
German printed patent application No. 2,525,263 suggests a transport device for sheet stock wherein several webs are juxtaposed and are more or less transported in parallel but independently from each other through the printer and separate switches are provided in order to monitor these different sheets or webs separately. This kind of an arrangement is on one hand dictated by the requirement of having several sheets transported in parallel through the same printer. A rather complicated transfer arrangement is necessary here. In accordance with a different mode of construction of a matrix printer, several feed paths for print stock are arranged on different sides of the print housing but require a specified feature with regard to the arrangement of the paper and sensing device.